Acurx Launches Clinical Trial Program for Ibezapolstat in Recurrent C. difficile Infection

Acurx Pharmaceuticals announced on March 9, 2026 that it will conduct a new clinical trial in patients with recurrent C. difficile Infection (rCDI) while its program in the broader CDI patient population is ready to advance to Phase 3 international clinical trials, subject to receiving appropriate funding. The clinical stage biopharmaceutical company is developing a new class of antibiotics for difficult-to-treat bacterial infections.

The new clinical trial in rCDI begins with an open-label pilot trial to gain experience with ibezapolstat (IBZ) in patients with multiply-recurrent CDI with at least 3 episodes of CDI within the past 12 months. This open-label trial will enroll up to 20 patients whose CDI has recurred at least twice following standard of care antibiotic treatment within the past 12 months. Trial start-up activities for this new clinical trial in rCDI will initiate later this month with the first patient expected to enroll in the fourth quarter this year.

The pilot trial will inform elements of a planned active-controlled, Phase 3 registration trial in the rCDI indication to be implemented following favorable results from the open-label 20 patient trial. Upon subsequent successful completion of the Phase 3 pivotal rCDI trial, Acurx plans to request FDA approval for treatment and prevention of rCDI under the FDA's Limited Population Pathway for Antibacterial and Antifungal Drugs.

In a Phase 2 trial, ibezapolstat was highly effective, achieving 96% clinical cure in 26 patients treating acute CDI with no recurrence in patients while sparing the gut microbiome. All 25 patients treated with IBZ who experienced a clinical cure of CDI were free of recurrence 1 month after treatment and 5 of 5 (100%) of these patients who were observed for 3 months after treatment remained free of recurrence.

Recent unpublished data from the laboratory at the University of Houston demonstrate that beneficial bacterial taxa persist in fecal samples from patients with rCDI despite multiple prior CDI treatments with the antibiotic standards of care, vancomycin and/or fidaxomicin, indicating that, following acute treatment with IBZ, these beneficial microorganisms will have the opportunity to repopulate the microbiome in a favorable way that may prevent recurrence. Results of this experimental data have been submitted in abstract form to the Anaerobe Society of the Americas scientific conference July 7-10, 2026, at Columbia University in New York and will be publicly disclosed shortly thereafter.

Acurx has previously been granted FDA QIDP and Fast-Track Designation and has received SME (Small and Medium-sized Enterprise) designation by the EMA.

The Executive Chairman stated that ibezapolstat has the potential to be the first agent to demonstrate clinical success in both the treatment of CDI and the prevention of rCDI, and such success would shift the paradigm of treatment and prevention of rCDI from two agents to one. C. difficile infection affects approximately 500,000 patients each year in the U.S., results in approximately 30,000 deaths, and generates a related public health cost burden of approximately $5 billion, of which $2.8 billion is related to rCDI.

More details about this new program will be discussed on the company's March 13, 2026 earnings call for full year and fourth quarter 2025 financial results.